I have a holly bush that is covered with black dust type stuff. I live in the northeast part of CT. and the bush must be 20 years old now. I admit I let it go without pruning for two years (along with the surrounding hedges). We've had so much rain this year. We normally have about two inches at this time of year, but in recent months & weeks we are at 9 inches of rain fall. I am wondering what I should do with the plant. The black rubs off easily and the branches also have the same blackness and white spotting also. Can I save this bush? It has always been a great looking bush. Thanking you in advance for your in put.